In recent years, a method has been being developed in which a power storage element formed of a secondary battery, an electric double layer capacitor, or the like is applied to an electric rolling stock controller; it is known that the electric rolling stock controller is configured in such away that superfluous regenerative electric power generated while a vehicle is braked during a regenerative period is stored and the stored electric power is utilized while the vehicle is accelerated during a power running period, so that the kinetic energy of the vehicle can effectively be utilized (e.g., refer to Patent Document 1). Patent Document 1 discloses that an electric rolling stock travels by means of electric power from a power storage element, without receiving electric power from an overhead line.    Patent Document 1: Japanese Patent Laid-Open Pub. No. 2006-14395